The present invention relates to a molding die and a manufacturing method of a molded product, and more particularly to a molding die for pressure molding and a manufacturing method of a molded product.
Generally, as a molding die for heating, pressurizing and molding a glass vitreous material, a molding die as shown in FIG. 6 is used. A conventional molding die comprises a tubular shell 21, a lower pattern 22, and an upper pattern 23. The lower pattern 22 is inserted and fixed at the lower end side of the shell 21. The upper pattern 23 is inserted from the upper end side of the shell 21, and is slidably inserted. A glass vitreous material 25 is disposed in this molding die 24, and is heated, pressurized and molded.
Hitherto, in such molding die 24, the tubular shell 21 was a columnar element made of a cemented carbide having a penetration hole. That is, the conventional shell 1 was an integrated one-body structure.
However, by using such conventional molding die 24, when a glass vitreous material 25 is heated, pressurized and molded, the glass vitreous material 25 spreads widely in the molding space in the molding die 24 in the molding process, or the glass vitreous material 25 sticks to the inner side of the shell 21. As a result, it was difficult to take out the glass molded product from the shell 21.
It is hence an object of the invention to present a molding die capable of taking out the molded product easily. Further, by using the molding die of the invention, a molded product having an excellent dimensional precision can be manufactured.
A molding die of the invention comprises:
(a) a shell having a penetration hole, the penetration hole having a lower opening and an upper opening,
(b) a lower pattern disposed to the lower opening of the shell, and
(c) an upper pattern slidably disposed from the upper opening of the shell,
in which the shell includes an outer shell and an inner shell disposed inside of the outer shell, the inner shell is composed of plural split shells, the inner shell can be separated from the outer shell, and the inner shell, lower pattern, and upper pattern form a cavity.
A manufacturing method of molded product of the invention comprises the steps of:
(a) combining an inner shell in an outer shell having a second penetration hole, and obtaining a shell having a penetration hole,
wherein the inner shell has plural split shells, and
the penetration hole is surrounded by the plural split shells,
(b) disposing the lower opening of the penetration hole of the shell to a lower pattern,
(c) placing a molding material in a cavity surrounded by the penetration hole and lower pattern,
(d) forming a molded product by inserting an upper pattern into the cavity from an upper opening of the penetration hole of the shell, and pressurizing the molding material while heating the molding material,
(e) separating the upper pattern and outer shell from the inner shell and lower pattern after the molded product formed by pressurizing is solidified, and
(f) taking out the molded product by separating the plural split shells, after step (e).
In this constitution, if the molded product sticks to the inner circumference of the shell, the molded product can be easily taken out of the molding die by separating the shell. Further, a molded product having a complicated convex and concave shape can be manufactured easily.